With a continuously growing population, it is becoming increasingly difficult to meet the world's energy needs and, simultaneously, to control carbon emissions to kerb greenhouse gas emissions which are considered responsible for global warming phenomena. These concerns have triggered a drive towards a more efficient use of electricity in an attempt to reduce energy consumption.
One such area of concern is lighting applications, either in domestic or commercial settings. There is a clear trend towards the replacement of traditional, relatively energy-inefficient, light bulbs such as incandescent or fluorescent light bulbs with more energy efficient replacements. Indeed, in many jurisdictions the production and retailing of incandescent light bulbs has been outlawed, thus forcing consumers to buy energy-efficient alternatives, for example when replacing incandescent light bulbs.
A particularly promising alternative is provided by solid state lighting (SSL) devices, which can produce a unit luminous output at a fraction of the energy cost of incandescent or fluorescent light bulbs. An example of such a SSL element is a light emitting diode (LED).
It is known to provide SSL lighting devices having a similar overall shape to incandescent light bulbs, for example, bulbous solid state lighting devices. Such devices can provide an appearance that is comparable with traditional lighting devices which can aid market penetration as customers may like or be accustomed to the appearance of incandescent light bulbs. These bulbous SSL devices may be used to replace incandescent light bulbs or used in similar applications to incandescent light bulbs. In particular, these SSL lighting devices may be particularly easy to retro-fit in place of incandescent light bulbs.
An example of a prior art bulbous SSL element-based lighting device comprises SSL elements mounted within the same glass bulb as used for incandescent bulbs. However, if the glass breaks the device may still be operable, even though the glass is broken, such that the user may be exposed to parts of the lamp carrying a high current and/or voltage. If a user then touches these parts there is a significant risk of electrical shock, which is potentially harmful.
DE19927142C1 discloses an automobile reflector lamp which has light source mounted on rear side of transparent carrier plate facing towards rear reflector. The contacts for the light source provided by the carrier plate brought into contact with counter-contacts when the carrier plate is fitted in the lamp. Helicoidal springs are used as contacts for ensuring sufficient contact pressure. However, safety issue is not considered and there is still potential risk of electrical shock when the lamp glass is broken due to the exposed contacts.